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CVE-2026-5958 Detail

Description

When sed is invoked with both -i (in-place edit) and --follow-symlinks, the function open_next_file() performs two separate, non-atomic filesystem operations on the same path: 1. resolves symlink to its target and stores the resolved path for determining when output is written, 2. opens the original symlink path (not the resolved one) to read the file. Between these two calls there is a race window. If an attacker atomically replaces the symlink with a different target during that window, sed will: read content from the new (attacker-chosen) symlink target and write the processed result to the path recorded in step 1. This can lead to arbitrary file overwrite with attacker-controlled content in the context of the sed process. This issue was fixed in version 4.10.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  CERT.PL
CVSS-B 2.1 LOW
Vector:  CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cert.pl/en/posts/2026/04/CVE-2026-5958 CERT.PL
https://www.gnu.org/software/sed/ CERT.PL

Weakness Enumeration

CWE-ID CWE Name Source
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition CERT.PL  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-5958
NVD Published Date:
04/20/2026
NVD Last Modified:
04/20/2026
Source:
CERT.PL